<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>03_CSS常用值</title>
    <style>
        h1 {

            color: rgb(255, 255, 255);
            color: rgb(0, 0, 0);

            color: rgb(255, 255, 0);
            color: rgb(0, 0, 255);

            color: rgb(255, 0, 0);
            color: rgb(0, 255, 255);

            color: rgb(0, 255, 0);
            color: rgb(255, 0, 255);

        }
        /* rgba()中四个数分别是:红,绿,蓝,透明度 */
        .d1 {
            background-color: rgb(255, 0, 0, 1);
        }
        .d2 {
            background-color: rgba(255, 0, 0, 0.5);
        }
        .d3 {
            background-color: rgba(255, 0, 0, 0.3);
        }
        .d4 {
            background-color: rgba(255, 0, 0, 0.1);
        }
        .d5 {
            background-color: rgba(255, 0, 0, 0.05);
        }
        .d6 {
            background-color: rgba(255, 0, 0, 0);
        }
        .dgi {
            width: 200px;
            height: 200px;
            background-image: url("../3.jpg");
        }
        .viewport {
            width: 100vw;
            height: 100vh;
            background-color: deepskyblue;
        }
    </style>
</head>
<body>
<div class="viewport"></div>

<h1>测速色值</h1>

<div class="d1" style="height: 100px;"></div>
<div class="d2" style="height: 100px"></div>
<div class="d3" style="height: 100px"></div>
<div class="d4" style="height: 100px"></div>
<div class="d5" style="height: 100px"></div>
<div class="d6" style="height: 100px"></div>
<div class="dgi"></div>

</body>
</html>